Device for detecting moisture for an arrangement for monitoring an access to a patient

ABSTRACT

A device for detecting moisture for an arrangement for monitoring an access to a patient for a system by which, via a flexible line, a liquid is fed to a patient and/or a liquid is fed out from the patient, and in particular for monitoring the vascular access in extra-corporeal blood treatment and particularly for monitoring a central venous catheter for acute dialysis includes at least a portion which can be deformed into a sleeve and placed around the circumference of the flexible line or of a connecting system. The portion in sleeve form has fastening means for fixing it in place in the position in which it surrounds the flexible line or the connecting system. The portion in sleeve form allows the device to be fastened quickly and securely to a flexible line or a connecting system.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication Ser. No. 61/669,186, filed on Jul. 9, 2012, and ApplicationNo. DE 10 2012 013 474.6, filed in the Federal Republic of Germany onJul. 9, 2012, each of which is expressly incorporated herein in itsentirety by reference thereto.

FIELD OF INVENTION

The present invention relates to a device for detecting moisture for anarrangement for monitoring an access to a patient for a system by which,via a flexible line, a liquid is fed to a patient and/or a liquid is fedout from the patient, and in particular for monitoring the vascularaccess in extra-corporeal blood treatment and particularly formonitoring a central venous catheter in acute dialysis. As well as this,the present invention also relates to an arrangement for monitoring anaccess to a patient which has a device for detecting moisture.

BACKGROUND INFORMATION

In the field of medical engineering, there are various known systemswith which, via a flexible line, liquids can be withdrawn from patientsor liquids can be fed to patients. The access to the patients isgenerally gained in this case by a catheter for insertion in organs ofthe body or by a needle for puncturing vessels. During the examinationor treatment, it has to be ensured that proper access exists to thepatient. It is therefore necessary for the patient access to bemonitored.

Proper access to the patient is also a particular prerequisite for thepieces of extra-corporeal blood treatment apparatus which have anextra-corporeal blood circuit. The known pieces of extra-corporeal bloodapparatus include for example pieces of dialysis apparatus and cellseparators which require access to the patient's vascular system. Inextra-corporeal blood treatment, blood is withdrawn from the patientalong a flexible arterial line having an arterial puncturing needle andis fed back to the patient along a flexible venous line having a venouspuncturing needle. In acute dialysis at intensive care stations on theother hand, what is used as a patient access is for example a centralvenous catheter in the patient's neck.

What is generally used to connect catheters and flexible lines formaking a patient access is the Luer connecting system which is wellknown in the medical field and whose connecting parts comprise an innerand an outer cone which form tapers. This connecting system is referredto as a Luer lock connection when, to secure the connection, the innerand outer cones are supplemented with a screw thread. Although Luer lockconnections provide a very high level of safety, it has been found inpractice that the connecting parts, if not properly handled or if usedtoo often or if there are faults in their material, may becomedisconnected or micro-cracks may develop in the material. U.S. PatentPublication No. 2010/0228231 therefore proposes securing the connectingparts of a Luer lock connecting system against unintentionaldisconnection with an additional means of fixing the connecting parts.

There are various known arrangements of different forms for monitoringthe vascular access. These known monitoring arrangements generally relyon the safety devices which are provided as standard in the pieces ofblood treatment apparatus and which trigger an immediate shutoff of theextra-corporeal blood circuit if there is not a proper vascular access.

There are known arrangements for monitoring a vascular access by aneedle which have a device for detecting moisture to enable the escapeof blood to be detected at the site of the puncture. The known devicesfor detecting moisture which are used in the known monitoringarrangements for the patient access take the form of a pad whichconsists of an absorbent material in which is embedded a moisturesensor.

Pads of an absorbent material which are applied to the patient's skinare described in, for example, International Patent Publication No. WO2006/008866, U.S. Patent Publication No. 2005/0038325 and U.S. Pat. No.6,445,304. The characteristic feature of the known pads is that themoisture sensor is embedded in the absorbent material and the absorbentmaterial is applied to the patient's skin.

International Patent Publication No. WO 99/24145 describes a device fordetecting moisture which has a housing, able to be closed off with alid, in which a moisture sensor is arranged. Provided in the housing areapertures for the needles and flexible lines to pass through. It is adisadvantage that the housing containing the moisture sensor isrelatively expensive to produce in large numbers and is relativelydifficult to handle in practice.

SUMMARY

An object underlying the present invention is to provide a device fordetecting moisture which can be inexpensively produced in large numbers.A further object of the present invention is to provide a device fordetecting moisture which is easy and safe to handle and which is verycomfortable to be carried on the patient. Underlying the presentinvention is also the object of providing an arrangement for monitoringan access to a patient which has a device of this kind for detectingmoisture.

The device according to the present invention for detecting moisture hasa moisture sensor which takes the form of an electrically conductivestructure. The moisture sensor of the device according to the presentinvention is connected to an arrangement for monitoring an access to apatient which may be part of a system by which, via a flexible line, aliquid is fed to a patient and/or a liquid is fed out from the patient.

The device according to the present invention for detecting moisture ischaracterised in that at least a portion of the device for detectingmoisture takes the form of a portion which can be deformed into a sleeveand which can be placed around the circumference of the flexible lineand/or of a system for connecting the flexible line. The portion insleeve form has fastening means for fixing the portion in sleeve form inplace in the position in which it surrounds the flexible line or theconnecting system.

The portion formed after the fashion of a sleeve allows the device fordetecting moisture to be fastened quickly and securely to a flexibleline or to a system for connecting the line. No additional fasteningmeans are required for this purpose. It is not for example necessary forthe device to be fixed to the flexible line, the connecting system orthe patient's skin with adhesive tape. This simplifies the handling ofthe device.

As well as this, it is also of advantage for the device according to thepresent invention to be easily able to be removed again from theflexible line after the treatment, which is important particularly whenit is used to monitor a central venous catheter. The device can easilybe detached from the flexible line even during the treatment.

In particular, the device according to the present invention can befastened in place in that region of the flexible line in which aconnecting system, such as a Luer connecting system for example, issituated. For this purpose, the portion able to be deformed into asleeve simply needs to be placed around the connecting system, thusenabling the point of connection to be monitored for leaks.

The device according to the present invention preferably has a layer notpermeable to liquid which is adjacent the patient and situated on theoutside and a layer absorbent of liquid which is remote from the patientand situated on the inside. What is achieved in this way is that bloodescaping at the point of the connection in the flexible line finds itsway directly to the moisture sensor. It also prevents sweat from thepatient's skin, or blood from a wound or from a leak in the set of bloodtubing at some point other than the venous access, or some other liquidfrom outside finding its way to the moisture sensor, thus preventingfalse alarms.

Whereas an additional means of securing a Luer connection which isdescribed in U.S. Patent Publication No. 2010/0228231 is only able toprevent the connection from disconnecting, the device according to thepresent invention also enables a slow loss of blood to be detected, duefor example to errors in making the connection in the flexible line orto faults in the material.

In a preferred exemplary embodiment, the connecting means of the portionable to be deformed into a sleeve have at least one elongated portionand at least one slot for the elongated portion to be pulled through.The elongated portion simply has to be pulled through the slot to fastenthe device in place. The sleeve can be pulled tightly closed when thisis done, thus causing the sleeve to surround the site of the connectionin the flexible line tightly.

To fix the elongated portion in the slot, the elongated portionpreferably has one or more barbs. If a plurality of barbs are provided,it is possible for the elongated portion to be fixed in differentpositions, thus enabling the portion in sleeve form of the device to beadapted to flexible lines or connecting systems of different dimensions.The barbs may also take the form of a continuous series of sawteeth.

In an alternative exemplary embodiment, the fastening means have an areawhich is provided with an adhesive or adhering layer. The adhesive oradhering layer is preferably a strip which is provided on the portionable to be deformed into a sleeve. The adhesive or adhering layer mayfor example also take the form of a hook-and-loop fastener.

Basically, the fastening means may be any means by which the relevantportions can, on the one hand, be connected together easily and can, onthe other hand, be easily detached from one another. The fasteningtogether of the relevant portions may for example be accomplished as aresult of the forming of loops or straps, hooks or eyes, buttons andbuttonholes or the like. A sliding-clasp fastener for example may evenbe provided for connecting the portions together.

In a further exemplary embodiment which is a particular preference, theelongated portion which is pulled through the slot is in particular acomposite material comprising a textile material and a film. Thestiffness of the strip can be increased by this composite material.

Increased security against the device according to the present inventionslipping off is achieved if the arrangement for fixing the portion insleeve form in place has a plurality of elongated portions. It is forexample possible for two strips to be provided which enclose theconnecting parts or the flexible line on both sides of the connectingsystem.

The device according to the present invention has connecting contacts toallow electrical contact to be made with the moisture sensor. The numberof connecting contacts will depend on the form the moisture sensortakes. The moisture sensor may for example comprise two connectingcontacts, the resistance between which is measured. Two furtherconnecting contacts may also be provided to allow a terminal resistor tobe connected. However, rather than a connecting strip having connectingcontacts, it is also possible for an electrical connecting line which isthen connected to the monitoring arrangement to be run from the deviceaccording to the present invention.

A preferred exemplary embodiment makes provision for the connectingcontacts to be formed at the end of an elongated portion which isconnected to the portion in the form of a sleeve. What is achieved inthis way is that the connecting contacts are physically separated fromthe moisture sensor. There is therefore no need for the region in whichthe electrical contact is made to be sterile, unlike the region in whichthe moisture sensor is situated. This is particularly advantageous whencentral venous catheters are being monitored.

In a particularly preferred exemplary embodiment, the connectingcontacts are arranged at the end of the elongated portion, which latteracts as a strip for pulling the portion in sleeve form closed. Thismakes it possible to dispense with an additional strip for makingelectrical contact with the moisture sensor.

The device according to the present invention preferably has a layer notpermeable to moisture which is adjacent the patient and situated on theoutside and a layer absorbent of liquid which is remote from the patientand situated on the inside. The electrically conductive structure of themoisture sensor is preferably embedded in the layer absorbent of liquidor is applied to the absorbent layer. The electrical conductivestructure need not extend over the entire area of the absorbent layerbecause, due to the absorptive capacity of the layer, it is enough formoisture to be detected in a sub-region of the area.

In a particularly preferred exemplary embodiment, the absorbent layer inwhich the electrically conductive structure is to be embedded is atextile material. The textile material is preferably a woven materialhaving non-conductive warp filaments and non-conductive weft filamentsand conductive warp filaments and conductive weft filaments, which areso arranged that the electrically conductive structure is formed in thewoven material. A woven material of this kind having an electricallyconductive structure is described in detail in International PatentPublication No. WO 2011/116943.

The electrically conductive structure may have one or more conductorswhich, in a plurality of portions, extend at least over a sub-region ofthe portion in sleeve form.

The portion able to be deformed into a sleeve may be of differentdimensions and shapes. In a preferred exemplary embodiment, the portionable to be deformed into a sleeve is a square-cornered portion whichassumes the shape of a cylindrical portion which surrounds the flexibleline or the connecting system.

An alternative exemplary embodiment makes provision for the portiondeformable as a sleeve to be a circular portion which is cut away forpart of its circumference. In this exemplary embodiment, the portionsurrounding the flexible line assumes the shape of a funnel. For theflexible line to be passed through, the portion which is cut away forpart of its circumference has in the centre a central, preferablycircular, cut-out.

The device according to the present invention can be produced in largenumbers by a weaving process without production involving any great costor complication. It can also be cut away and sterilised with no greattechnical cost or complication and can be made available in sterile formin suitable packaging as a disposable sensor

The arrangement according to the present invention for monitoring anaccess to a patient, and in particular for monitoring a vascular accessin extra-corporeal blood treatment and particularly for monitoring acentral venous catheter, has the device according to the presentinvention for detecting moisture, which is connected to the monitoringarrangement. The monitoring arrangement may trigger an audio and/orvisual and/or tactile alarm if moisture is detected. It is also possiblefor a control signal to be generated for action in the control systemcontrolling the system by which, via a flexible line, a liquid is fed tothe patient and/or a liquid is fed out from the patient.

The arrangement according to the present invention for monitoring apatient access may form a separate unit or may be part of the system bywhich a liquid is fed to the patient and/or a liquid is fed out from thepatient, and may in particular be part of the extra-corporeal bloodtreatment apparatus. If the monitoring arrangement according to thepresent invention is part of the blood treatment apparatus, themonitoring arrangement may make use of certain sub-assemblies orcomponents which are present anyway in the blood treatment apparatus.

Exemplary embodiments of the device according to the present inventionare explained in detail below with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the principal components of a blood treatment apparatuswhich has an arrangement for monitoring a vascular access.

FIG. 2 is a simplified view of a first exemplary embodiment of deviceaccording to the present invention for detecting moisture which isfitted to a connecting system for connecting a central venous catheterto a flexible line.

FIG. 3 shows a second exemplary embodiment of the device shown in FIG. 2before being fitted to the connecting system.

FIG. 4 is a simplified view of a third exemplary embodiment of deviceaccording to the present invention.

FIG. 5 is a simplified view of a fourth exemplary embodiment of device.

FIG. 6 is a simplified view of a fifth exemplary embodiment of device.

FIG. 7 is a simplified view of a sixth exemplary embodiment of device.

FIG. 8 is a simplified view of a seventh exemplary embodiment of device.

FIG. 9 is a simplified view of an eighth exemplary embodiment of device.

FIG. 10 is a simplified view of a ninth exemplary embodiment of device.

DETAILED DESCRIPTION

FIG. 1 shows the principal components of a blood treatment apparatus,and in particular a haemodialysis apparatus A for acute dialysis, whichhas an arrangement B for monitoring a vascular access and in particulara vascular access which has a central venous catheter. The monitoringarrangement B is part of the haemodialysis apparatus A in the presentembodiment. The dialysis apparatus will first be described by referenceto FIG. 1.

The haemodialysis apparatus A has a dialyser 1 which is divided into ablood chamber 3 and a dialysis-fluid chamber 4 by a semi-permeablemembrane 2. The vascular access to the patient is obtained by a centralvenous catheter 5 which is connected to the patient's neck. The centralvenous catheter 5 is part of the extra-corporeal blood circuit I, whichis merely indicated and which includes the blood chamber 3 of thedialyser 1 and comprises the flexible lines 6, 7. A blood pump 8 isprovided to pump the blood in the extra-corporeal circuit.

The dialysis-fluid circuit II of the dialysis apparatus A comprises adialysis-fluid source 10 to which a dialysis-fluid infeed line 11, whichruns to the inlet of the dialysis-fluid chamber 4 of the dialyser 1, isconnected. Running off from the outlet of the dialysis-fluid chamber 4of the dialyser 1 is a dialysis-fluid outfeed line 12 which runs to anoutlet 13. A dialysis-fluid pump 14 is connected into the dialysis-fluidoutfeed line 12.

Responsible for controlling the dialysis apparatus is a central controlunit 15 which operates the blood and dialysis-fluid pumps 8, 14 viacontrol lines 16, 17. The central control unit 15 is connected by a dataline 18 to an alarm unit 19 which gives a visual and/or audio and/ortactile alarm if anything untoward happens.

In the present exemplary embodiment, the monitoring arrangement B, whichis only shown schematically, is used to monitor a Luer lock connector 9having parts 9A and 9B, for connecting the central venous catheter 5 toa flexible line 9C belonging to the extra-corporeal blood circuit I. Themonitoring arrangement B has a device 20 for detecting moisture which isarranged at the point 21 of the connection to the flexible line. Thisdevice 20 is only shown in schematic form in FIG. 1. As well as this,the monitoring arrangement B also has an analysing arrangement 22 whichis electrically connected to the device 20 by a connecting line 23. Theconnecting line 23 is connected to the device 20 by an electricalconnector 23A.

The analysing arrangement 22 is connected to the central control unit 15of the dialysis apparatus A by a data line 24. In the event of bloodescaping from the point of connection 21 to the flexible line andwetting the device 20 for detecting moisture, the analysing arrangement22 of the monitoring arrangement B generates a control signal which thecentral control unit 15 receives via the data line 24, the centralcontrol unit 15 then making an intervention in the blood treatment. Thecontrol unit 15 stops the blood pump 8 and generates an alarm signal sothat the alarm unit 19 gives an audio and/or visual and/or tactilealarm.

FIG. 2 shows a first exemplary embodiment of device according to thepresent invention for detecting moisture. The device has a textilesubstrate material 30 which is a woven material in the exemplaryembodiment. The woven material has a portion 30A in the form of asquare-cornered blank which can be placed round the circumference of aflexible line or of a connecting system for connecting a catheter to aflexible line. Connected to one of the two long sides of thesquare-cornered portion 30A, in a central position between the two shortsides, is an elongated portion 30B which acts as a connecting strip fora connector (not shown) for connecting the device according to thepresent invention to the analysing arrangement 22 of the arrangement Bfor monitoring the vascular access.

The absorbent woven material 30 has an outer side 31A adjacent thepatient's skin and an inner side 31B remote from the patient's skin. Onthe outer side 31A, the woven material is connected, preferably over itsentire area, to a film 32 of plastics material which is not permeable toliquid and is not electrically conductive. As well as this, the film 32of plastics material also gives the woven material 30 the requisitestrength and/or stiffness, particularly in the region of the elongatedportion 30B for connection to the connector. As an alternative to theuse of a film of plastics material, a hydrophobic coating may beprovided on one side of the woven material. A polyester woven materialcan be made hydrophobic by for example the use of fluorine-containinggases in a low-pressure plasma.

The device for detecting moisture has a moisture sensor 34 which ismerely indicated in FIG. 2 and which comprises an electricallyconductive structure which is embedded in the woven material (FIG. 2).The woven material 30 comprises for this purpose non-conductive warpfilaments and non-conductive weft filaments and conductive warpfilaments and conductive weft filaments, which are so arranged as toproduce the electrically conductive structure which is made up of aplurality of conductor portions 35, 36 positioned orthogonally to oneanother which are merely indicated. The individual portions of conductor35, 36 extend over sub-regions of the square-cornered portion 30A ableto be formed into a sleeve and run to the end of the elongated portion30B for connection to the connector (not shown), the portions ofconductor forming two electrodes. At the end of the elongated portion30B, the portions of conductor take the form of connecting contacts 33.The outer connecting contacts 33A are used for the connection formeasuring the resistance of the moisture sensor while the innerconnecting contacts 33B are used as the connection for a terminalresistor.

Along one short side, the portion 30A able to be formed into a sleevehas an adhesive or adhering layer 37 in strip form which is indicated bya single-hatched area in FIG. 2. The adhesive or adhering layer 37 mayalso be provided along both short sides of the portion 30A, or it may beprovided on the inside or outside of the portion 30A. What is crucial isfor the portion 30A to be able to be placed around the circumference ofthe connecting system or the flexible line and for the portions whichoverlap one another to be able to be connected together when the portion30A in sleeve form surrounds the connecting system or the flexible linetightly. The adhesive or adhering layer 37 may for example be aself-adhesive film or a hook-and-loop fastener. The film of plasticsmaterial which is applied to the outside of the woven material may forexample take the form of an adhesive film in the edge region.

The device for detecting moisture can easily be removed again from theflexible line or the connecting system by releasing the adhesive oradhering layer connection, thus making the connecting system accessibleagain.

If the device for detecting moisture is placed against the flexible lineor the connecting system, a leak will cause the woven material 30 to bewetted with moisture, such as blood for example, as a result of whichthe woven material will absorb a full charge of the liquid. This willchange the resistance between the outer connecting contacts 33A of theelectrically conductive structure. The sensor is sensitive whereverconductive filaments of the first electrode can be short-circuited bymoisture to conductive filaments of the second electrode.

FIG. 3 shows a second exemplary embodiment of the device 20 according tothe present invention before it is placed against the flexible line orthe latter's connecting system, i.e., when the device is not yet in theform of a sleeve. This exemplary embodiment differs from the firstexemplary embodiment only in that the elongated portion 30B is connectedto the square-cornered portion 30A not centrally but laterally. Partswhich correspond to one another have therefore been identified by thesame reference numerals. FIG. 3 clearly shows the portions of conductor35, 36 which are positioned orthogonally to one another. The conductorportions 35, 36, which extend over sub-regions of the square-corneredportion 30A able to be formed into a sleeve, run to the end of theelongated portion 30B for connection to the connector (not shown). Theintersections at which electrical contact is made in the woven materialbetween the warp and weft filaments extending orthogonally to oneanother are identified by circles. A woven material of this kind havingan electrically conductive structure is described in InternationalPatent Publication No. WO 2011/116943, which is hereby incorporated byreference in its entirety.

FIGS. 4 to 10 show alternative exemplary embodiments of the device fordetecting moisture which differ from the exemplary embodiments whichhave been described with reference to FIGS. 2 and 3 essentially in theform taken by the fastening means.

In the case of the exemplary embodiments shown in FIGS. 4 to 8, all thatare shown are the outlines. The electrically conductive structure whichis situated on the inside of the woven material has not been shownbecause the exemplary embodiments shown in FIGS. 4 to 8 differ from theexemplary embodiments shown in FIGS. 2 and 3 essentially only in thefastening means and the differing shape.

In the exemplary embodiment shown in FIG. 4, the portion 48A able to beformed into a sleeve is a substantially square-cornered portion.Connected to one of the sides of the square-cornered portion 48A in acentral position is an elongated portion 48B which once again forms aconnecting strip for a connector (not shown) for connecting the devicefor detecting moisture to the analysing arrangement of the monitoringarrangement. On the opposite side from the elongated portion 48B, thesquare-cornered portion 48A has a slot 49 whose width is slightlygreater than the width of the elongated portion 48B. If the portion 48Ais placed round the flexible line or the connecting system, the sleevecan be pulled tight by pulling the elongated portion 48B through theslot 49 and then fixing it in place. Hence, in this exemplary embodimenttoo, the elongated portion serves not only to fix the sleeve in placebut also to connect up the moisture sensor electrically.

FIG. 5 shows an alternative exemplary embodiment which differs from theexemplary embodiment shown in FIG. 4 only in that instead of one centralelongated portion being provided on one side of the square-corneredportion 48A there are two elongated portions 48C and 48D provided whichare in off-center positions. Parts which correspond to one another haveonce again been given the same reference numerals. In the exemplaryembodiment shown in FIG. 5, only one of the two elongated portions, suchas the left-hand portion 48C for example, takes the form of a connectingstrip for the connector. On the opposite side from the elongatedportions 48C and 48D, the square-cornered portion 48A has two slots 49Aand 49B arranged in off-center positions, through which the elongatedportions 48C, 48D are pulled to pull the sleeve tight.

FIGS. 6 to 8 show alternative exemplary embodiments which differ fromthe exemplary embodiment shown in FIG. 4 only in the particular formtaken by the elongated portion 48B. Whereas in the exemplary embodimentshown in FIG. 4 the elongated portion has to be fixed in place withadditional fixing means, the elongated portion 48B in FIG. 6 has a barb50 which prevents the elongated portion 48B from being pulled out of theslot 49 again. FIG. 7 shows an exemplary embodiment having two barbs 50Aand 50B arranged at a distance from one another. It is however alsopossible for further barbs to be provided to enable the sleeve to bedrawn together to the desired diameter.

FIG. 8 shows a further exemplary embodiment which differs from theexemplary embodiments described above only in that the barb 51 isincorporated in the square-cornered portion 48A. In the region in whichthe elongated portion 48B is connected to the square-cornered portion48A, the said elongated portion 48B which is connected to thesquare-cornered portion 48A forms a cut-out in the square-corneredportion, the outline of the longitudinal sides of the elongated portion48B being formed by incisions 52A, 52B in the square-cornered portion48A. This allows the elongated portion 48B to be folded out of thesquare-cornered portion 48A to free the barb 51. It is also possible fora plurality of barbs to be formed in this way.

FIG. 9 shows an exemplary embodiment in which the portion 53 able to beformed into a sleeve is a circular portion which is cut away for part ofits circumference. In the present exemplary embodiment, the circularportion 53 is cut away over an angle of 90°. In the center, the centerportion 53 having the cut-away has a central circular cut-out 54 whosediameter is greater than the diameter of the flexible line or connectingsystem. Connected to one half of the circular portion 53 having thecut-away is an elongated portion 55 which once again forms theconnecting strip for the electrical connector. Situated in the otherhalf of the portion 53 are two slots 56A and 56B spaced apart from oneanother through which the elongated portion 55 can be pulled. In thisexemplary embodiment, the elongated portion 55 can be fixed in place bybeing pulled through both the slots from above and below respectively.To fit the device 20 for detecting moisture, the circular portion 53having the cut-away is placed around the flexible line or the connectingsystem, the flexible line or connecting system coming to rest in thecentral cut-out 54. The circular portion 53 having the cut-away is thenshaped into a sleeve in the form of a funnel which surrounds theflexible line and the connecting system. The fixing in place is thenperformed with the connecting strip 55. The portions of conductor 35, 36of the electrically conductive structure 34 which forms the moisturesensor are shown in FIG. 9.

FIG. 10 shows an alternative exemplary embodiment which differs from theexemplary embodiment shown in FIG. 9 only in the arrangement of theconductor portions 35, 36 of the electrically conductive structure 34.In the exemplary embodiment shown in FIG. 10, the electricallyconductive structure 34 has not only the conductor portions 35, 36 butalso additional conductor portions 35A, 36A, thus giving the moisturesensor shown in FIG. 10 greater sensitivity than the sensor shown inFIG. 9.

What is claimed is:
 1. A device for detecting moisture for anarrangement for monitoring an access to a patient for a system by which,via a flexible line, a liquid is fed to a patient and/or a liquid is fedout from the patient, or for monitoring a vascular access inextra-corporeal blood treatment, the device comprising: a moisturesensor including an electrically conductive structure; at least aportion of the device that is deformable into a sleeve to be placedaround a circumference of the flexible line or a connecting system forthe flexible line; and a fastening device for fixing the portion insleeve form in place in a position surrounding the flexible line or theconnecting system.
 2. The device according to claim 1, wherein thefastening device includes at least one elongated portion and at leastone slot through which the elongated portion is pulled.
 3. The deviceaccording to claim 2, wherein, to fix in place the elongated portionwhich is pulled through the slot, the elongated portion includes one ormore barbs.
 4. The device according to claim 2, wherein the elongatedportion is a composite material comprising a textile material and afilm.
 5. The device according to claim 1, wherein the fastening deviceincludes an area or a strip provided with an adhesive or adhering layer.6. The device according to claim 1, further comprising: connectingcontacts configured to allow electrical contact to be made with themoisture sensor, the connecting contacts being formed at an end of anelongated portion connected to the portion deformable into the sleeve.7. The device according to claim 1, further comprising: a layer notpermeable to moisture which is adjacent the patient and situated on anoutside of the portion deformable into the sleeve; and a layer absorbentof liquid which is remote from the patient and situated on an inside ofthe portion deformable into the sleeve.
 8. The device according to claim7, wherein the layer absorbent of liquid is a textile material includingthe electrically conductive structure.
 9. The device according to claim1, wherein the electrically conductive structure is embedded in atextile material.
 10. The device according to claim 9, wherein thetextile material is a woven material including non-conductive warpfilaments, non-conductive weft filaments, conductive warp filaments andconductive weft filaments arranged such that the electrically conductivestructure is formed in the woven material.
 11. The device according toclaim 1, wherein the electrically conductive structure has at least oneconductor which, in a plurality of portions, extends at least over asub-region of the portion in sleeve form.
 12. The device according toclaim 1, wherein the portion deformable into the sleeve is asquare-cornered portion.
 13. The device according to claim 1, whereinthe portion deformable into the sleeve is a circular portion which iscut away for part of its circumference.
 14. The device according toclaim 13, wherein the circular portion includes a central cut-out in itscenter.
 15. An arrangement for monitoring an access to a patient for asystem by which, via a flexible line, a liquid is fed to a patientand/or a liquid is fed out from the patient, or for monitoring avascular access in extra-corporeal blood treatment, the arrangementcomprising: the device for detecting moisture according to claim 1.